Manufacturing & Prototyping

Improved Joining of Metal Components to Composite Structures

Uncured composite material is intertwined with metal studs, then cured. Systems requirements for complex spacecraft drive design requirements that lead to structures, components, and/or enclosures of a multi-material and multifunctional design. The varying physical properties of aluminum, tungsten, Invar, or other high-grade aerospace metals when utilized in conjunction with lightweight composites multiply system level solutions. These multi-material designs are largely dependent upon effective joining techniques, which create a “monolithic,” well-integrated and seamlessly functional structure.

Posted in: Briefs, Manufacturing & Prototyping, Joining, Composite materials, Materials properties, Metals, Jet engines, Spacecraft


Machined Titanium Heat-Pipe Wick Structure

Wicks are fabricated separately, then inserted in tubes. Wick structures fabricated by machining of titanium porous material are essential components of lightweight titanium/ water heat pipes of a type now being developed for operation at temperatures up to 530 K in high-radiation environments. In the fabrication of some prior heat pipes, wicks have been made by extruding axial grooves into aluminum — unfortunately, titanium cannot be extruded. In the fabrication of some other prior heat pipes, wicks have been made by in-situ sintering of metal powders shaped by the use of forming mandrels that are subsequently removed, but in the specific application that gave rise to the present fabrication method, the required dimensions and shapes of the heat-pipe structures would make it very difficult if not impossible to remove the mandrels due to the length and the small diameter.

Posted in: Briefs, Manufacturing & Prototyping, Water, Fabrication, Heat resistant alloys, Titanium, Parts, Hoses


Sealing and External Sterilization of a Sample Container

This method would enable safe transport of a biologically hazardous sample. A method of (1) sealing a sample of material acquired in a possibly biologically contaminated (“dirty”) environment into a hermetic container, (2) sterilizing the outer surface of the container, then (3) delivering the sealed container to a clean environment has been proposed. This method incorporates the method reported in “Separation and Sealing of a Sample Container Using Brazing” (NPO-41024), NASA Tech Briefs, Vol. 31, No. 8 (August 2007), page 42. Like the previously reported method, the method now proposed was originally intended to be used to return samples from Mars to Earth, but could also be used on Earth to transport material samples acquired in environments that contain biological hazards and/or, in some cases, chemical hazards.

Posted in: Briefs, Manufacturing & Prototyping, Biological sciences, Containers


System for Removing Pollutants From Incinerator Exhaust

A system for removing pollutants — primarily sulfur dioxide and mixed oxides of nitrogen (NOx) — from incinerator exhaust has been demonstrated. The system is also designed secondarily to remove particles, hydrocarbons, and CO. The system is intended for use in an enclosed environment, for which a prior NOx-and-SO2-removal system designed for industrial settings would not be suitable. The incinerator exhaust first encounters a cyclone separator, a primary heat exchanger, and a fabric filter that, together, remove particles and reduce the temperature to 500 °C. The exhaust then passes through a porous bed, maintained at ≈ 450 °C, that contains Na2CO3, which absorbs SO2.

Posted in: Briefs, Manufacturing & Prototyping, Exhaust emissions, Nitrogen oxides


Templates for Deposition of Microscopic Pointed Structures

These structures can be used as field emitters in plasma television screens. Templates for fabricating sharply pointed microscopic peaks arranged in nearly regular planar arrays can be fabricated by a relatively inexpensive technique that has recently been demonstrated. Depending on the intended application, a semiconducting, insulating, or metallic film could be deposited on such a template by sputtering, thermal evaporation, pulsed laser deposition, or any other suitable conventional deposition technique. Pointed structures fabricated by use of these techniques may prove useful as photocathodes or field emitters in plasma television screens. Selected peaks could be removed from such structures and used individually as scanning tips in atomic force microscopy or mechanical surface profiling.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Microscopy, Fabrication


Making Superconducting Welds Between Superconducting Wires

Parts of a superconducting circuit can be made from different metals. A technique for making superconducting joints between wires made of dissimilar superconducting metals has been devised. The technique is especially suitable for fabrication of superconducting circuits needed to support persistent electric currents in electromagnets in diverse cryogenic applications. Examples of such electromagnets include those in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) systems and in superconducting quantum interference devices (SQUIDs).

Posted in: Briefs, TSP, Manufacturing & Prototyping, Electromagnetic compatibility, Wiring, Fabrication, Welding, Conductivity


Method for Thermal Spraying of Coatings Using Resonant-Pulsed Combustion

High-volume, high-velocity surface deposition allows protective metal coatings to be applied to otherwise vulnerable surfaces. A method has been devised for high-volume, high-velocity surface deposition of protective metallic coatings on otherwise vulnerable surfaces. Thermal spraying is used whereby the material to be deposited is heated to the melting point by passing through a flame. Rather than the usual method of deposition from the jet formed from the combustion products, this innovation uses non-steady combustion (i.e. high- frequency, periodic, confined bursts), which generates not only higher temperatures and heat transfer rates, but exceedingly high impingement velocities an order of magnitude higher than conventional thermal systems. Higher impingement rates make for better adhesion. The high heat transfer rates developed here allow the deposition material to be introduced, not as an expensive powder with high surface-area-to-volume, but in convenient rod form, which is also easier and simpler to feed into the system. The nonsteady, resonant combustion process is self-aspirating and requires no external actuation or control and no high-pressure supply of fuel or air.

Posted in: Briefs, TSP, Manufacturing & Prototyping, Heat transfer, Spraying, Metals, Combustion and combustion processes


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